Reference is made to a book authored by N. J. Harrick entitled "Internal Reflection Spectroscopy", published by Interscience Publishers in 1967. This book provides a complete description of the principles underlying this technology, and also describes the construction and configuration of so-called internal reflection elements (IREs) used in such analysis equipment. Attention is especially drawn to pages 223-227 which describes the application of IREs for use in liquid cells. Reference is further made to U.S. Pat. Nos. 3,393,603; 4,602,869; and 4,730,882, which are also directed to different IRE and liquid cell geometries.
In general, it is important to many companies that process liquids to be able to conduct in-line analysis or analysis of samples in the simplest and most economic manner. As is known, many conventional spectrometers generate a radiation beam which upon emerging from the instrument converges to a region in the so-called sampling space or compartment of the instrument, and if not intercepted or used will continue back into the instrument for spectral analysis. It is common to locate the IRE element or transfer optics for the IRE element in the sampling space so as to maintain the original focussing conditions. At the same time, it is desirable that the IRE element, which must physically contact the liquid, be suitably positioned for effective and efficient use.